Another large earthquake predicted in Wellington area in next week

Another large shake on both sides of Cook Strait is highly likely over the next week, experts say.

The chance of a jolt of magnitude 5 or more in the next seven days is 90 per cent, according to GNS Science seismologists, and the likelihood of a magnitude 6 or more quake is about 21 per cent.

Seismologist Caroline Holden warned people to be vigilant and expect another large shake. Since Friday afternoon's 6.6 tremor, there had been another 59 aftershocks reaching magnitude 4 or more, by 4pm yesterday.

Dr Holden's colleague Martin Reyners said the area near Seddon where the earthquakes were recurring was known as an active one. There was a magnitude 6 quake there in 1966, and another in 1977.

The level of horizontal acceleration, which is the amount of movement people feel from a quake, was similar to that felt during the Christchurch earthquakes, but not as significant.

"It's a different experience for everyone, depending on what soil your house is built on. At its worst acceleration, there were reports of people not being able to stay standing upright," he said.

The sequence of quakes was slowly tracking southwest, away from Wellington, but on to land in Marlborough.

"Friday's quake was situated so that the people of Seddon were sitting pretty much on top of it, which explains the damage. Each quake changes the stresses in the fault. In areas where the stress has gone up, near a fault, it can trigger another event."

In the case of the recent quakes, there had been some triggering as the stresses shifted south. This would mean the effects would be felt less in Wellington, but more in Seddon. Thanks to Fairfax media for permission to run this article.

I think of all the graphics and predictions I have seen in the last year, the one below from stuff explains the situation well. Please make sure you stock up on food, and read what to do in the Yellow Pages smd ahare with friends and family. Stay safe.

June 28, 2012 – NEW ZEALAND – GNS Science and University of Nevada-Renoscientists have found that the southern part of the 800 kilometre-long fault which runs along the western edge of the Southern Alps from Marlborough to Milford Sound causes quakes of around magnitude 8 every 330 years on average. Dating leaves and seeds from a river terrace at Hokuri Creek near Lake McKerrow in far northwestern Southland, just north of Milford Sound, revealed 24 Alpine Fault quakes between 6000BC and the present. Other research has found the most recent was in 1717, meaning the next may be only 30 or 40 years away, based on averages. Professor Richard Norris, from the geology department at Otago University, said the Alpine Fault had the highest level of probability for rupture of any fault in New Zealand. “Westland obviously is at high risk, with widespread damage likely and roads, bridges and other transport links likely to be badly affected (as well as the tourist trade),” he said. The fault crossed the main West Coast road in many places, and with an estimated 8m displacement would completely destroy it. “Intensities further east in places like Queenstown, Te Anau, Wanaka and Mt Cook will be high enough to cause landslips and do damage,” Norris said. “Further east in the major cities of Christchurch and Dunedin, the intensities will be lower but the duration of shaking could still be sufficient to damage poorly constructed buildings…and possibly cause some liquefaction.” Places such as Nelson, Wellington and Invercargill could also expect to feel some shaking. Project leader Kelvin Berryman of GNS Science said “a major earthquake in the near future would not be a surprise. Equally it could be up to 100 years away. The bottom line is, if not in our lifetimes then increasingly likely in our children’s or our grandchildren’s.” The study’s findings, published today in the journal Science, were new and internationally significant, Berryman said. Auckland University biostatics professor Thomas Lumley said the intervals between quakes on the Alpine Fault tended to be quite close to the average interval, with relatively little spread. –Stuff